One type of a semiconductor device includes a plurality of semiconductor chips stacked in one package. Such a semiconductor device can reduce a size of the device.
In such a semiconductor device, a plurality of micro bumps are formed on each of the semiconductor chips, and the bumps enable transmission of an electrical signal between the semiconductor chips to be at a fast speed. When a semiconductor chip including the micro bumps are stacked onto another semiconductor chip including the micro bumps, alignment marks formed on the semiconductor chips are checked by a camera, and the semiconductor chips are aligned based on captured images. Then, the stacked semiconductor chips are connected by applying heat, compression force, ultrasonic waves, or the like thereto. However, the stacked semiconductor chips may still be misaligned.